Chapter on the Prayer Times (Mawaqit)
Tahdhīb al-Aḥkām|Volume 2|Book 1|Chapter 13
اَلْحَسَنُ بْنُ مَحْبُوبٍ عَنْ عَلِيِّ بْنِ رِئَابٍ عَنْ زُرَارَةَ قَالَ: قُلْتُ لِأَبِي جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ بَيْنَ اَلظُّهْرِ وَ اَلْعَصْرِ حَدٌّ مَعْرُوفٌ فَقَالَ« لاَ»
Al-Hasan ibn Mahbub narrated from Ali ibn Ri'ab from Zurarah who said:
I said to Abu Ja'far عليه السلام: “Is there a known limit between Dhuhr and Asr?” Imam عليه السلام said: "No."
- Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 273
- Ṣaḥīḥ al-Tahdhīb, p. 161